A word processing system is disclosed in which a text stream is stored for recall and editing. The characters in the text stream can be derived from a number of keyboard character sets but each character must be identified according to its character set to be properly printed or displayed. When the system operator moves, copies or deletes blocks of text the correct keyboard character sets must be maintained. When blocks of text are inserted or deleted the keyboard character sets are determined for the interfacing text blocks. When there is a transition from one keyboard character set to another, a character set change code is inserted to indicate the correct keyboard character set for the immediately following text.